Updates docs style guide with codeblock examples
Updates docs style guide with codeblock examples

Long story short, make sure commands can be copied and pasted easily,
but it's OK to violate that rule by prepending `$` for clarity's sake in
a full terminal session, with text printed to stdout inlined in the
block.

ageis/securedrop,ehartsuyker/securedrop,heartsucker/securedrop,ehartsuyker/securedrop,ehartsuyker/securedrop,ehartsuyker/securedrop,conorsch/securedrop,ageis/securedrop,micahflee/securedrop,garrettr/securedrop,micahflee/securedrop,heartsucker/securedrop,ageis/securedrop,garrettr/securedrop,conorsch/securedrop,ehartsuyker/securedrop,conorsch/securedrop,heartsucker/securedrop,ehartsuyker/securedrop,micahflee/securedrop,micahflee/securedrop,ageis/securedrop,heartsucker/securedrop,garrettr/securedrop,heartsucker/securedrop,conorsch/securedrop,garrettr/securedrop,conorsch/securedrop